Presently available are a number of hydraulic tools used for assembling, shaping, forming, and otherwise, manipulating materials. By way of example, U.S. Pat. No. 4,189,817 issued on Feb. 26, 1980 and entitled "HYDRAULIC ASSEMBLY TOOL FOR TUBE FITTINGS" is directed to a highly useful and successful tool having a fixed and a removable jaw, both jaws of whioh are capable of precise coaxial movement in order to force together a tube or pipe fitting. This U.S. Patent is incorporated herein by reference. A similar hydraulic assembly tool is depicted in FIGS. 13 and 14. As can be seen in FIG. 13, the prior art hydraulic assembly tool 20 includes a body structure 22 whioh houses a hydraulic cylinder 24 into which is reciprocally mounted piston 26. A shaft 28 extends from the piston 26. Hydraulic fluid, entering through port 30, urges the piston 26 out of the hydraulic cylinder 24 and spring 32 connected between the piston 26 and the hydraulic cylinder 24 causes the piston 26 to be drawn back into the hydraulic cylinder 24 once hydraulic pressure is relieved.
The shaft 28 is guided by a bore 34. Mounted onto the shaft 28 is a movable jaw 36 which extends substantially radially from a central axis 38 of the shaft 28. Movable jaw 36 is press fit onto the shaft 28. Located in a radially manner from the bore 34 is a fixed jaw 40. Between the fixed jaw 40 and the movable jaw 36, fittings can be positioned. With hydraulic fluid introduced into the hydraulic cylinder 24, the movable jaw 36 is urged toward the fixed jaw 40 causing the fitting to be compressed about and join two pipes or tubes together.
As a result of repeated usage of the tool, there is wearing at the upper bearing surface 42 of the cylindrical bore 34 as well as the upper bearing surface 44 of the cylindrical shaft 28. Thus, overtime, the bore 34 becomes elongated. Additional wear occurs between the upper bearing surfaces 46 and 48 of the hydraulic cylinder 24 and the piston 26, respectfully. Further, uneven wear occurs on the bearing surface 50 which is defined by the movable jaw 36 and which surface 50 bears upon the body structure 22 immediately above the hydraulic cylinder 24. Additionally, flexure in the connection between the movable jaw and piston causes misalignment of the two jaws.